Lol, instead of 2x I will use 1.5x for A7 and 1.8x for A7r. So, at equivalency, the M1 will be slightly better?

Sorry but apparently you still didn't get it. As you can see from the diagram above, the E-M1 is about 1.5 EV ahead for equivalent images and about 0.5 EV behind for non-equivalent ones (same exposure, different DoF).

Hopefully, you also remember this part of our exchange:

Henry said: and the difference, even per DxO, they rate the ISO performance for the cameras as EM1/A7/A7r as 757/2248/2746. Two stops would have been 3028. So we all agree?

Anders W said: Not quite. While these figures too show the difference to be less than two stops, they underestimate the actual advantage of the E-M1 for equivalent images. The DR curve posted by Lab D provides a better indication with regard to shadow noise, which in turn is the most apparent problem in high ISO shooting. What the curves indicate is that the E-M1 is about 1.5 stops ahead of the A7/A7R for equivalent images (DoF held constant) and about 0.5 EV behind at the same exposure (and different DoF).

But the A7/r do allow trading DOF and noise.

So of course does the E-M1. It's just a matter of how far you want to take that trade. If, as a rule, you don't want more shallow DoF than you can get with a fast MFT prime, you will lose rather than gain signal-noise performance by choosing the A7/r.

We are only as relentless as you force us to be.

Lol, that is because you take every statement and keep adding and rebutting.

No that's because you persist, in the most arrogant manner (just look at your first reply to Lab D here) in repeating your factual errors.

Lab D has a history of being very arrogant to a number of specific people, including me, hence the tone of my response. Sorry if that hit a nerve, but I am merely responding to him.

As to the graph that you keep posting, I think that is a very specific interpretation. It is an 8Mp print measured graph, not the actual sensor/image resolution, and there have been lots of debates on this.

Each camera model begins to exhibit visible noise at their rated ISO level - I can attest to that from my own usage, as well as the various reports that are out there (dpreview).

DxOMark also reports an overall sensor score, and lens+camera combinations. You may agree or disagree with their metrics, but they do help interpreting the data.

DxOMark shows, per the ll article, that larger sensors do not maintain the efficiency of smaller sensors, so "there may be some headroom left for the engineers/manufacturers". And it highlights your claims that smaller sensor perform better, in comparison.

But I agree with the DxOMark interpretation: larger sensor outperform smaller sensor. At least in terms of noise. They have hang their ratings on this for a long time, and many do agree to their way of classifying cameras (and sensors).

How much, and by which difference - that is a long debate going on here - technical or not, when I see images side by side, I see less resolution and more noise on smaller sensor cameras. Perhaps the images are not matched in equivalency, and your reasoning holds up, but I would not shoot a small sensor camera at high ISO while I would not be afraid to shoot a larger sensor camera at high ISO.

Theory or not, practicality prevails. I am happy with my low light/low noise results. Perhaps your equivalency analysis holds merit, I am trading shallow DOF when lights are low (indoors), or I use the flash to get a different effect.

With a smaller format sensor, I already feel like being in a corner - hence the migration to larger sensors.

And sorry, per all the discussions, I do not see m43 matching FF for low light applications.

You may say that DOF gets too shallow, I would say that DOF gets too deep.